Opening/Closure Status

The grounds of the USBG will be closed September 18, 2021. On other days, all outdoor gardens are currently open. The Conservatory and public restrooms remain closed, due to the closure of the U.S. Capitol campus buildings. Please monitor for updates on operating status. USBG resources can be accessed online, including educational materials, virtual tours, and online programs by visiting

Clay's hibiscus or Kokiʻo ʻula

Hibiscus clayi
Plant Botanical Name: 
Hibiscus clayi
USBG Plant Location: 
Conservatory Room Location: 
Plant Threat Level: 

Known as Koki`o `ula in Hawaii, Hibiscus clayi is an endangered tree endemic to the dry forests in the Nounou Mountains on the island of Kaui. Today, in large part due to livestock grazing, development and invasive plants there is only one naturally occurring population with only four individual plants. Because of habitat protection efforts and the propagation by botanic gardens, such as National Tropical Botanic Gardens, there is a slow increase in the numbers of plants found in forest preserves. Private landowners and public land managers also are working to carefully manage use of these threatened habitats.